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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 01:02:30 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 01:02:30 +0000 |
commit | 76cb841cb886eef6b3bee341a2266c76578724ad (patch) | |
tree | f5892e5ba6cc11949952a6ce4ecbe6d516d6ce58 /drivers/infiniband/hw/cxgb4/id_table.c | |
parent | Initial commit. (diff) | |
download | linux-upstream.tar.xz linux-upstream.zip |
Adding upstream version 4.19.249.upstream/4.19.249upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/infiniband/hw/cxgb4/id_table.c')
-rw-r--r-- | drivers/infiniband/hw/cxgb4/id_table.c | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/drivers/infiniband/hw/cxgb4/id_table.c b/drivers/infiniband/hw/cxgb4/id_table.c new file mode 100644 index 000000000..724d23297 --- /dev/null +++ b/drivers/infiniband/hw/cxgb4/id_table.c @@ -0,0 +1,111 @@ +/* + * Copyright (c) 2011 Chelsio Communications. All rights reserved. + * + * This software is available to you under a choice of one of two + * licenses. You may choose to be licensed under the terms of the GNU + * General Public License (GPL) Version 2, available from the file + * COPYING in the main directory of this source tree, or the + * OpenIB.org BSD license below: + * + * Redistribution and use in source and binary forms, with or + * without modification, are permitted provided that the following + * conditions are met: + * + * - Redistributions of source code must retain the above + * copyright notice, this list of conditions and the following + * disclaimer. + * + * - Redistributions in binary form must reproduce the above + * copyright notice, this list of conditions and the following + * disclaimer in the documentation and/or other materials + * provided with the distribution. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS + * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN + * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + */ +#include <linux/kernel.h> +#include <linux/random.h> +#include "iw_cxgb4.h" + +#define RANDOM_SKIP 16 + +/* + * Trivial bitmap-based allocator. If the random flag is set, the + * allocator is designed to: + * - pseudo-randomize the id returned such that it is not trivially predictable. + * - avoid reuse of recently used id (at the expense of predictability) + */ +u32 c4iw_id_alloc(struct c4iw_id_table *alloc) +{ + unsigned long flags; + u32 obj; + + spin_lock_irqsave(&alloc->lock, flags); + + obj = find_next_zero_bit(alloc->table, alloc->max, alloc->last); + if (obj >= alloc->max) + obj = find_first_zero_bit(alloc->table, alloc->max); + + if (obj < alloc->max) { + if (alloc->flags & C4IW_ID_TABLE_F_RANDOM) + alloc->last += prandom_u32() % RANDOM_SKIP; + else + alloc->last = obj + 1; + if (alloc->last >= alloc->max) + alloc->last = 0; + set_bit(obj, alloc->table); + obj += alloc->start; + } else + obj = -1; + + spin_unlock_irqrestore(&alloc->lock, flags); + return obj; +} + +void c4iw_id_free(struct c4iw_id_table *alloc, u32 obj) +{ + unsigned long flags; + + obj -= alloc->start; + + spin_lock_irqsave(&alloc->lock, flags); + clear_bit(obj, alloc->table); + spin_unlock_irqrestore(&alloc->lock, flags); +} + +int c4iw_id_table_alloc(struct c4iw_id_table *alloc, u32 start, u32 num, + u32 reserved, u32 flags) +{ + int i; + + alloc->start = start; + alloc->flags = flags; + if (flags & C4IW_ID_TABLE_F_RANDOM) + alloc->last = prandom_u32() % RANDOM_SKIP; + else + alloc->last = 0; + alloc->max = num; + spin_lock_init(&alloc->lock); + alloc->table = kmalloc_array(BITS_TO_LONGS(num), sizeof(long), + GFP_KERNEL); + if (!alloc->table) + return -ENOMEM; + + bitmap_zero(alloc->table, num); + if (!(alloc->flags & C4IW_ID_TABLE_F_EMPTY)) + for (i = 0; i < reserved; ++i) + set_bit(i, alloc->table); + + return 0; +} + +void c4iw_id_table_free(struct c4iw_id_table *alloc) +{ + kfree(alloc->table); +} |